Browsing by Subject "Streptococcus pyogenes"

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  • Wu, H; Liu, J; Miao, S; Zhao, Y; Zhu, H; Qiao, M; Saris, Per Erik Joakim; Qiao, J (2018)
    To overcome the adverse impacts of environmental stresses during growth, different adaptive regulation mechanisms can be activated in Lactococcus lactis In this study, the transcription levels of eight transcriptional regulators of L. lactis subsp. lactis F44 under acid stress were analyzed using quantitative reverse transcription-PCR. Eight gene-overexpressing strains were then constructed to examine their influences on acid-resistant capability. Overexpressing ythA, a PspC family transcriptional regulator, increased the survival rate by 3.2-fold compared to the control at the lethal pH 3.0 acid shock. Moreover, the nisin yield was increased by 45.50%. The ythA-overexpressing strain FythA appeared to have higher intracellular pH stability and nisin-resistant ability. Subsequently, transcriptome analysis revealed that the vast majority of genes associated with amino acid biosynthesis, including arginine, serine, phenylalanine, and tyrosine, were predominantly upregulated in FythA. Arginine biosynthesis (argG and argH), arginine deiminase pathway, and polar amino acid transport (ysfE and ysfF) were proposed to be the main regulation mechanisms of YthA. Furthermore, the transcription of genes associated with pyrimidine and exopolysaccharide biosynthesis were upregulated. The transcriptional levels of nisIPRKFEG genes were substantially higher in FythA, which directly contributed to the yield and resistance of nisin. Three potential DNA-binding sequences were predicted by computer analysis using the upstream regions of genes with prominent changes. This study showed that YthA could increase acid resistance and nisin yield and revealed a putative regulation mechanism of YthA.IMPORTANCE Nisin, produced by Lactococcus lactis subsp. lactis, is widely used as a safe food preservative. Acid stress becomes the primary restrictive factor of cell growth and nisin yield. In this research, we found that the transcriptional regulator YthA was conducive to enhancing the acid resistance of L. lactis F44. Overexpressing ythA could significantly improve the survival rate and nisin yield. The stability of intracellular pH and nisin resistance were also increased. Transcriptome analysis showed that nisin immunity and the biosynthesis of some amino acids, pyrimidine, and exopolysaccharides were enhanced in the engineered strain. This study elucidates the regulation mechanism of YthA and provides a novel strategy for constructing robust industrial L. lactis strains.
  • Kiilavuori, Anna; Pätäri-Sampo, Anu (2021)
    • Esimurrosiässä vulvovaginiitti on tyttöjen yleisin gynekologinen vaiva. Sille altistavat anatomiset ja ¬fysiologiset syyt ja hygieniatavat. • Hyvä anamneesi ja kajoamaton tutkiminen ovat diagnostiikan perusta. • Yleisin on epäspesifinen tulehdus. Hoitona on hygieniatapojen korjaaminen avohoidon ohjein. • Toistuva tai jatkuva oireilu, verinen tai muu runsas emätinvuoto viittaavat spesifiseen tulehdukseen, vierasesineeseen tai muuhun harvinaiseen syyhyn. • Streptococcus pyogeneksen ja kihomatojen aiheuttama tulehdus voidaan hoitaa avohoidossa. Muut epäilyt lähetetään erikoissairaanhoitoon.
  • Donders, G; Greenhouse, P; Donders, F; Engel, U; Paavonen, J; Mendling, W (2021)
    There has been an increasing worldwide incidence of invasive group A streptococcal (GAS) disease in pregnancy and in the puerperal period over the past 30 years. Postpartum Group A streptococci infection, and in particular streptococcal toxic shock syndrome (TSS) and necrotizing fasciitis, can be life threatening and difficult to treat. Despite antibiotics and supportive therapy, and in some cases advanced extensive surgery, mortality associated with invasive group A streptococcal postpartum endometritis, necrotizing fasciitis, and toxic shock syndrome remains high, up to 40% of postpartum septic deaths. It now accounts for more than 75,000 deaths worldwide every year. Postpartum women have a 20-fold increased incidence of GAS disease compared to non-pregnant women. Despite the high incidence, many invasive GAS infections are not diagnosed in a timely manner, resulting in potentially preventable maternal and neonatal deaths. In this paper the specific characteristics of GAS infection in the field of Ob/Gyn are brought to our attention, resulting in guidelines to improve our awareness, early recognition and timely treatment of the disease. New European prevalence data of vaginal GAS colonization are presented, alongside two original case histories. Additionally, aerobic vaginitis is proposed as a supplementary risk factor for invasive GAS diseases.
  • Kachroo, Priyanka; Eraso, Jesus M.; Olsen, Randall J.; Zhu, Luchang; Kubiak, Samantha L.; Pruitt, Layne; Yerramilli, Prasanti; Cantu, Concepcion C.; Saavedra, Matthew Ojeda; Pensar, Johan; Corander, Jukka; Jenkins, Leslie; Kao, Lillian; Granillo, Alejandro; Porter, Adeline R.; DeLeo, Frank R.; Musser, James M. (2020)
    A fundamental goal of contemporary biomedical research is to understand the molecular basis of disease pathogenesis and exploit this information to develop targeted and more-effective therapies. Necrotizing myositis caused by the bacterial pathogen Streptococcus pyogenes is a devastating human infection with a high mortality rate and few successful therapeutic options. We used dual transcrip-tome sequencing (RNA-seq) to analyze the transcriptomes of S. pyogenes and host skeletal muscle recovered contemporaneously from infected nonhuman primates. The in vivo bacterial transcriptome was strikingly remodeled compared to organisms grown in vitro, with significant upregulation of genes contributing to virulence and altered regulation of metabolic genes. The transcriptome of muscle tissue from infected nonhuman primates (NHPs) differed significantly from that of mock-infected animals, due in part to substantial changes in genes contributing to inflammation and host defense processes. We discovered significant positive correlations between group A streptococcus (GAS) virulence factor transcripts and genes involved in the host immune response and inflammation. We also discovered significant correlations between the magnitude of bacterial virulence gene expression in vivo and pathogen fitness, as assessed by previously conducted genome-wide transposon-directed insertion site sequencing (TraDIS). By integrating the bacterial RNA-seq data with the fitness data generated by TraDIS, we discovered five new pathogen genes, namely, S. pyogenes 0281 (Spy0281 [dahA]), ihk-irr, slr, isp, and ciaH, that contribute to necrotizing myositis and confirmed these findings using isogenic deletion-mutant strains. Taken together, our study results provide rich new information about the molecular events occurring in severe invasive infection of primate skeletal muscle that has extensive translational research implications. IMPORTANCE Necrotizing myositis caused by Streptococcus pyogenes has high morbidity and mortality rates and relatively few successful therapeutic options. In addition, there is no licensed human S. pyogenes vaccine. To gain enhanced understanding of the molecular basis of this infection, we employed a multidimensional analysis strategy that included dual RNA-seq and other data derived from experimental infection of nonhuman primates. The data were used to target five streptococcal genes for pathogenesis research, resulting in the unambiguous demonstration that these genes contribute to pathogen-host molecular interactions in necrotizing infections. We exploited fitness data derived from a recently conducted genome-wide transposon mutagenesis study to discover significant correlation between the magnitude of bacterial virulence gene expression in vivo and pathogen fitness. Collectively, our findings have significant implications for translational research, potentially including vaccine efforts.
  • Rissanen, Valtteri (Helsingin yliopisto, 2019)
    Tutkimuksen tarkoituksena oli selvittää osastohoitoa vaatineen akuutin otiitin ja otomastoidiitin aiheuttaman kuulonaleneman palautumistaipumusta HYKS Korva-, Nenä- ja Kurkkutautien klinikassa vuosina 2017-2018. Aihetta on edeltävästi tutkittu hyvin vähän. Hypoteesin mukaan kuulonalenema on laadultaan osittain tai täysin palautuvaa. Tutkimus on rajattu akuutteihin infektioihin. Kroonisemmat infektiot ja sairaudet on rajattu aiheen ulkopuolelle eikä niitä käsitellä tässä tutkimuksessa ollenkaan. Potilasaineisto kerättiin HYKS Korva-, Nenä- ja kurkkutautien klinikan osaston KO6 potilastiedoista. Aineistoon valikoitui yhteensä 24 potilasta. Potilasaineistossa oli 12 miestä ja 12 naista. Lapsia (alle 18v) oli neljä. Sisäänottokriteereinä oli positiivinen A-streptokokkinäyte, vähintään kaksi audiogrammia, vähintään 21 vuorokauden seuranta-aika eikä kuulonalenema saanut johtua muusta syystä, kuten traumasta. Ilmajohtokuulokynnykset paranivat kaikilla mitatuilla taajuuksilla tilastollisesti merkitsevästi. Suurin paraneminen, 42,1 dB tapahtui taajuudella 8000 Hz (p < 0,001). Minimiarvoissa kuulokynnysten paranemista seurannan aikana tapahtui kaikilla muilla taajuuksilla paitsi 250 Hz (paraneminen 1,42 dB, p = 0,85). PTA -arvo parani keskimäärin 32 dB (p < 0,001). Akuutin otiitin tai otomastoidiitin aiheuttama kuulonalenema, tyypistään tai vaikeusasteestaan riippumatta, vaikuttaa tämän tutkimuksen perusteella osittain tai täysin palautuvalta. Paraneminen on tilastollisesti merkittävää joko yksittäisiä taajuuksia (paitsi minimiarvo taajuudella 250 Hz) tai PTA -arvoja tarkastellessa. Tutkimuksen potilasaineisto on varsin suppea ja laajempia tutkimuksia tulosten luotettavuuden lisäämiseksi tarvitaan tulevaisuudessa.
  • Laakso, Juha T.; Rissanen, Valtteri; Ruotsalainen, Eeva; Korpi, Jarkko; Laulajainen-Hongisto, Anu; Sivonen, Ville; Sinkkonen, Saku T. (2021)
    Objective To describe the characteristics, diagnostics, treatment, and outcome of severe acute otitis media (AOM) and acute mastoiditis (AM) caused by group A beta-hemolytic streptococcus (GAS). Study design A retrospective cohort study. Methods The yearly incidence of inpatient care-needing GAS AOM/AM patients in our hospital catchment area between 2002 and 2018 was investigated. A detailed analysis was performed for cases treated during the last GAS epidemic in 2017-2018. Anamnesis, signs and symptoms, pure-tone audiometry results, treatment, complications, and outcome were collected from medical charts. Patients responded to an otology-specific health-related quality of life survey (EOS-16) 1.5 to 3 years after their treatment. Results The number of GAS infections peaks at approximately 7-year intervals. During 2017 and 2018, altogether 37 patients (29 adults and 8 children) were hospitalized due to GAS AOM/AM. AM was diagnosed in 14 (38%) patients. The disease progression was typically very rapid. At presentation, all patients had severe ear pain, 68% tympanic membrane perforation and discharge, 43% fever, and 43% vertigo. In pure-tone audiometry, there was usually a marked mixed hearing loss at presentation. There was a significant recovery in both air and bone conduction thresholds; the pure tone average improvement from presentation was 32.3 +/- 14.8 dB. Rapid strep tests (RST) proved to be more sensitive than bacterial culture in identifying GAS as a cause of AOM/AM. Conclusion GAS AOM/AM has a rapid onset. Hearing loss usually includes a sensorineural component, which is usually reversible with adequate treatment. RST seems to be useful in detecting GAS from middle ear discharge. Level of Evidence 4.
  • Ivaska, Lauri; Kuitunen, Mikael (2020)
    Kun teinitytön kurkkukipu ei alkanut helpottua antibioottikuurilla, hänet ohjattiin erikoissairaanhoidon päivystykseen.